Review article

اضغط هنا لتنزيل الملف

If the present large volumes of nitrogen-containing wastewater of domestic and industrial origin are discharged into the environment without proper treatment, they lead to extensive soil and water pollution. Proper elimination of pollutants from these effluents is essential in industrialized countries and is becoming increasingly important from an environmental and human health point of view in developing and emerging countries. Beside the conventional nitrogen removal process (lithoautotrophic nitrification and denitrification), novel and cost-effective biological nitrogen elimination processes have been developed, including simultaneous nitrification and denitrification, anaerobic ammonium oxidation (Anammox), and its combined system (completely autotrophic nitrogen removal over nitrite, Canon). This review summarizes the recent studies dealing with agricultural, domestic and industrial wastewaters regarding their nitrogen content. Traditional and novel biological nitrogen elimination technologies are reviewed.  Furthermore, recent studies dealing with temperature, dissolved oxygen, nitrate concentration, salinity, pH or the free ammonia concentration as factors affecting the nitrogen removal efficiency have also been incorporated